The project deals with three main areas: A) Transumbilical portal vein catheterization will be performed on subjects requiring surgical exploration. The peripheral and portal vein glucagon response to glucose and arginine in diabetic and non-diabetic subjects will be compared. B) Certain aspects of the control mechanism of glucagon secretion will be examined during this grant period. The effect of lipids on glucagon secretion will be accessed as well as an attempt to characterize the adrenergic control mechanism involved in glucagon secretion. C) A perfusion apparatus has been set up to study dynamic aspects of insulin and glucagon secretion.